32 Impact of Population Growth on Environment

Dr. Vijeta

Contents:

1. Introduction

2. Consequences of Population Growth

2.1. Environment and Ecological Consequences

2.2. Acidification

2.3.Global Warming

2.3.1.Ozone Depletion

2.4. Urbanization

2.5. Change due to disposal of waste material

2.6. Desertification

2.7. Water Supply

2.8. Food Security

2.9. Nutrition

3. Summary

1. Introduction

Man is continuously trying to tame the nature for his benefit. Domestication of environmental elements up to the threshold level is not harmful to natural balance. However, excessive use or rather misuse of environmental resources makes the environment vulnerable. With an increasing population, natural and man induced environmental disasters are causing increasing damage, loss of life and displacement of population. The dimensions of human vulnerability to environmental conditions have socio-economic as well as ecological dimensions which are strongly being manifested when the communities are not capable of coping with the impacts.

Fig-1: Human Population Growth

Source: https://www.google.co.in

2. Impact of Population Growth

2.1. Environment and Ecological Consequences

Rapid population growth could lead to environmental deterioration.In many developing countries, continued population growth has resulted in pressureon land, fragmentation of land holding, collapsing of fisheries, shrinking forests,rising temperatures, loss of plant and animal species.Severe pressure on forests due to rate of resource use and nature of use.Adverse effects on species diversity,Conversion of habitat to some other land use such as agriculture, urban development,forestry operation. In India, 70-80 per cent of fresh water marshes and lakes inGangetic flood plains had been lost in last 50 years.The following things are not favorable to environment and ecosystem-

Tropical deforestation and destruction of mangroves for commercial needs and fuelwoods is used.
Poaching and illegal harvesting of wildlife which is a threat to ecosystem and environment.
Increase in agricultural area, high use of chemical fertilizers, pesticides, andweedicides, water stagnation, soil erosion, soil salinity, and low productivity.
Degradation of coastal and other aquatic ecosystems for domestic sewage, pesticides,fertilizers, and industrial effluents.

Fig.2: Population growth and Consequences

Source: https://www.google.co.in

Environmental degradation is a result of the dynamic interplay of socio-economic,institutional and technological activities. Environmental changes may be driven bymany factors including economic growth, population growth, urbanization,intensification of agriculture, rising energy use and transportation.Environmental pollution is one of the serious problems faced by the people in the country, especially in urban areas, which not only experiences a rapid growth of population due to high fertility, low mortality and increasing rural-urban migration, but also industrialization which is accompanied by growing number of vehicles.According to the World Development Indicatorsreport in 1997,1.5 billion people live exposed to dangerous levels of air pollution,1 billion live without clean water and 2 billion live without sanitation. Population impacts on the environment primarily through the use of natural resources and production of wastes and is associated with environmental stresses like biodiversity, air and water pollution and increased pressure on arable land. India is the world’s sixth largest and second fastest growing producer of greenhouse gases. Delhi, Mumbai and Chennai are three of the world’s ten most populated cities.Increase in the human population activity, pollute the environment and disturb the ecosystem and above all and first one is the pollution. Pollution may be found in air, waterand soil, which directly imbalance the ecosystem and environment.

Air pollution: The World Health Organization (WHO) defines air pollution as “substances put into the air by the activity of mankind into concentrati onssufficient to cause harmful effects to health, property, crop yield or to interferewith the enjoyment of property”.The urban air pollution has grown across India in the last decade is alarming. Themain factors accounts to urban air quality deterioration are growing industrializationand increasing vehicular pollution, industrial emissions, automobile exhaust and theburning of fossil fuels kills thousands and live many more to suffer mainly fromrespiratory damage, heart and lung diseases.An automobile exhaust accounts a sizable part of pollution. Their effect on humanhealth is particularly of concern. Road transport accounts for a major share of airpollution load in mega cities.India is expected to have 51metro cities by 2021.The number of vehicles on Indian roads is estimated to increase by nine times by thetune of the century out of which 65 % to 70 % shall be two wheelers or three wheelers.Urban transport demand is expected to grow more than 2.6 times by 2020 at the existing modelsplit in larger medium sized cities.At the existing model split, the urban air quality is expected to deteriorate faster in the21st century, as two-wheeler population would be as high as 86.13 % of the total vehiclesused for passenger transportation.The enhanced green house effect, acidification, and ozone depletion, are all examples of atmospheric pollution that has occurred mainly after industrialization, urbanization, and deforestation.

Water Pollution:Water pollution is the pollution of introduction into fresh or ocean waters of chemical, physical, or biological material that degrades the quality of the water and affects the organisms living in it. This process ranges from simple addition of dissolved or suspended solids to discharge of the most insidious and persistent toxic pollutants such as pesticides, heavy metals, and non-degradable, bio accumulative, chemical compounds(http://tandice bsolutions.com).Soil Pollution: Land is often used as a recipient for treatment of wastes. Land also receives waste spills and this is the degradation of the earth’s land surface through misuse of the soil by poor agricultural practices, mineral exploitation, industrial waste dumping, and indiscriminate disposal of urban wastes.(http://tandice bsolutions.com).

2.2. Acidification: Atmospheric emissions of acidifying substances such as sulphur dioxide (SO2) and nitrogen oxides (NOx), mainly from the burning of fossil fuels, can persist in the air for up to a few days and thus can be transported over thousands of kilometres, when they undergo chemical conversion into acids (Sulphuric and nitric). The primary pollutants Sulphur dioxide, nitrogen dioxide and ammonia (NH3), together with their reaction products, lead after their deposition to changes in the chemical composition of the soil and surface water. This process interferes with ecosystems, leading to what is termed ‘acidification’. The decline of forests in Central and Eastern Europe and the many ‘dead’ lakes in Scandinavia and Canada are examples of damage which are, in part, due to acidification. Modern forestry and agriculture contribute to but can also be affected by acidification. Acidifying substances also play a role in the greenhouse effect. Furthermore, nitrogen oxides contribute to the ozone problems (build-up of tropospheric ozone, depletion of stratospheric ozone) and together with ammonia, contribute to the nitrogen fertilisation of natural terrestrial ecosystems; with phosphate they contribute to eutrophication in water (https://www.eea.europa.eu). It is yet another problem of environmental degradation between 17to 22 kms in stratosphere. The problem is considered to be acute in industrialcountries, and in parts of Asia-Pacific regions, Northeast India, Thailand, Japan,China, and South Korea.The main gases involved: nitrogen oxides, especially sulpher dioxide, nitrogendioxide, and nitrous oxide. This acidification leads to acid rains, affecting theforests and the fish.

2.3. Global Warming:Over the last century, human activity has led to a dramatic increase in the amount of greenhouse gases in the atmosphere. Most experts agree that this build-up of greenhouse gases has contributed to an increase of 1.3 degrees Fahrenheit in the Earth’s average surface temperature over the past 100 years. Current rates of greenhouse gas build-up will cause further warming and induce additional changes in the climate system that would very likely be larger than those observed during the 20th century. The expected consequences of such warming include major disruptions to agriculture, water supplies, and the diversity of life on Earth. Hurricanes and typhoons are likely to become more intense. Precipitation is expected to increase at high latitudes and decrease in subtropical areas (Mogelgaard, 2008).

2.3.1. Ozone Depletion:Many of human activities are badly affecting the atmosphere. Ozone depletion is one of those examples. Life is protected from UV rays by stratospheric ozone layer which acts as a shield or sun screen. Approximately 90% ozone is present in stratosphere at the height of 10 to 17 kilometer and is called ozone layer while remaining 10% is present in troposphere. Medium frequency UV radiations (200 nm to 315 nm) are absorbed 97 to 99% by the ozone layer . Ozone (O3) is colourless just like oxygen (O2) but it has very harsh odour. It is very rare as compared to oxygen. The process of ozone formation is called as photolysis. When the UV radiations from sun strike the O2 molecules, it causes splitting of O2. Oxygen molecules react with oxygen atoms in the upper atmosphere to form ozone. The ozone layer is basically naturally occurring gas in the region of stratosphere where ozone particles are accumulated . Ozone layer is also naturally broken down but there is a balance between its formation and natural depletion. As a result the total amount of ozone remains constant. But ozone layer thickness varies with altitude and seasonal change. Ozone concentration is highest between 19 – 23 km. Most of ozone is formed at equator where there is maximum sunshine but with winds it travels at high altitude and get accumulated in stratosphere . Ozone Hole Ozone hole is created in the region where ozone layer has been depleted. The term “Ozone hole” is applied when the depletion level is below 200 Dobson Unit (D.U). Ozone holes are first discovered in Antarctica in 1970. Few years ago ozone holes are also discovered in arctic region. Since 2000 rate of ozone depletion is increasing 0.5 percent per year. Due to depletion of Ozone, UV rays are penetrating in troposphere and leading to more ozone formation in troposphere which is causing injurious effects on our health as ozone is toxic for our body.In addition to increase in concentrations of greenhouse gases,acidification, human activities have caused changes in the ozone layer, whichhave serious implications for human health as well as for the earth’s ecosystem.Ozone is important for filtering the U V radiation and thus acts as a screen againstthe occurrence of skin cancers, cataracts, and other diseases of the eyes.Major causes of ozone depletion are CFCs (Cholor-fluoro-carbons), used inaerosol propellants, refrigerants, cleansers for electronic components, solventsand in the production of foamed plastics.Ozone depletion is affecting the human health and environment negatively, as it allows the penetration of UV radiations to reach the Earth. These radiations can cause severe diseases in humans such as skin cancer, eye damage and genetic mutations etc. Furthermore the ozone depletion is affecting the aquatic life, biogeochemical cycles, air quality and also contributing in Global warming (Anwar, et al, 2016).

2.4. Urbanization

For developing countries: population living in cities has almost doubled since 1960:from <22 % to >40%.In developed regions: 61 % to 76 %.By 2030 nearly 5 billion (61 %) of the world’s 8.1 billion people will live in cities.Cities and towns have become the engines of social change and rapid economicdevelopment. Urbanization is associated with improved access to education,employment, and health care.Problems due to urbanization: development of basic minimum services, housing,water supply, sewage, and solid wastes disposal, increasing waste generation at home,offices, and industries, coupled with poor waste disposal facilities result in rapidenvironment deterioration.Increasing automobiles add to air pollution.Persisting poverty in urban and semi-urban areas, awareness about the glaringinequities in close urban setting may lead to social unrest.Failure of government to provide adequate habitat for human development has lead tothe emergence of squatter settlements and the slums. The problem of slums andsquatter is of growing concern in third world countries.

2.5. Change due to disposal of waste material

The high energy consumption and high population densities of the urban societies,give rise to large quantities of waste water and sewage as well as domesticrubbish.Sewage can also cause pollution by promoting bacterial growth, which is aproblem acute in India, Indonesia, Malaysia, Pakistan, and Philippines.Industrial wastes which consists of chemicals, detergents, metals and syntheticcompounds besides solid wastes and garbage poses potential threat to humanhealth.Examples include Mercury poisoning impairs sensory, visual, auditory functions.The nuclear wastes contain radio-active isotopes which generate large quantitiesof heat. The disposal of nuclear waste is a serious danger to the biosphere.Besides this, it creates ecological problems also, for example, incidence of childhood leukemia occurs in population close to nuclear reactors.

2.6. Desertification: Desertification is a condition of human-induced land degradation that occurs in arid, semiarid and dry sub-humid regions (precipitation/potential evapotranspiration or P/ETP 0.05 to 0.65) and leads to a persistent decline in economic productivity (> 15% of the potential) of useful biota related to a land use or a production system. Climatic variations intensify the decline in productivity, restorative management mitigates it. Dry lands or territories susceptible to desertification occupy 39.7% (~ 5.2 billion ha) of the global terrestrial area (~ 13 billion ha). Desertification is caused primarily by over-exploitation of natural resources beyond their carrying capacity and due to which natural ecosystem and environment disturbs (Katyal and Vlek, 2000).climatic change is an important cause of desertification, yet theincreasing human pressure exerted through over grazing, deforestation for fuelwood, and expansion of agriculture, are main causes of the same.It is a long term degradation of dry lands, resulting either from overuse by manand his animals, or from natural causes, such as climatic fluctuations.

2.7. Water Supply

Water demand substantially exceeds sustainable water supply, and it is estimated that currently 8 % of the global population are living in countries affected by water stress, by 2020; about one-fourth of the human population may be facing chronic and recurring shortage of fresh water.On the other hand, excessive use of water has led to water logging and increasing salinity, which could have adverse impact on India’s food production.Aquatic environment is one manifestation of the water circulation of the Earth. People rely on limited quantity of water; therefore, water becomes scarce as world population increases so rapidly. Water qualities are set to be safe enough for people’s use and environmental conservation. WHO developed the drinking water quality guidelines, which supports individual country to establish its own national water quality standards. Microbial aspects have prior importance with their severity and extent of contamination. For agriculture, irrigation water may cause salinization if it contains large quantity of salts. Salinization deteriorates the productivity of agricultural land and eventually it becomes heath land. Water contamination directly affects aquaculture. The death of aquatic organisms is mainly caused by poisoning, asphyxiation, or epidermal lesion by corrosive chemicals (https://www.eolss.net).

2.8. Food Security

Definition of food security adopted at the World Food Summit (WFS) in November 1996: “Food security exists when all people at all times have physical or economic access to sufficient safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life” (FAO, 1996). To meet a growing global demand for food and fodder, one can opt for increasing yields through intensification and/or for extending the land base used for agricultural cultivation. Intensification and concentrating food production in the most productive regions may appear the most efficient way to use the land. However, risks to food security may be increased, because supply chains become more vulnerable and because of pollution. Loss of crop diversity, decline of pollinators and increased vulnerability of monocultures to diseases are additional stress factors. On the other hand, regional or local self-sufficiency and the reliance on extensive farming systems would require more cultivated land at the expense of natural habitats(https://www.eea.europa.eu).It is estimated that the global population will grow to 9 billion by 2050, and the food production will double; improvement in purchasing power and changing dietary habits may add to the requirement of food-grains.Therefore, in the next 5 decades, the food and nutrition could become critical in many parts of the world, especially in developing countries and pockets of poverty in the developed countries.

2.9. Nutrition

Rapid environmental changes are profoundly altering the relationships between humans and the ecosystems in which they live. These changes include overpopulation, loss of biological resources, ecosystem destruction associated with industrial and commercial development, climatic change, urbanization, modern agriculture employing pesticides and other inputs, and erosion of food crop diversity. As community development priorities merge with those of environmental conservation, it becomes increasingly clear that unless human populations meet their basic survival needs they cannot afford to conserve. At the same time unless local communities protect the environments around them they have limited hope to thrive beyond the short term. As nutrition represents the most fundamental of human needs, it provides a useful perspective from which to address this para dox. Nutrition research provides essential information on how environmental degradation can lead to major nutrition-related health problems such as malnutrition, infectious disease, and contamination (Padulosi, and Hodgkin, 1999). For Example: Growing population in India, has lead topoverty, ill-health, low-literacy, lack of safe-drinking water, sanitation, andhealth care, all this further contributes to the wide-spread prevalence ofinfections, and ill-health in not only children, but also in adults.The major nutritional problems include kwashiorkor, marasmus, beri-beri,goiter, night-blindness, and anemia. Though with the advancement in technology, the frequency of these problems have reduced, but the milder forms of chronic energy deficiency and micro- nutrient deficiencies continue to be widely prevalent in adults and children.

3. Summary

The rapid population growth and economic development in country are degrading the environment through the uncontrolled growth of urbanization and industrialization, expansion and intensification of agriculture, and the destruction of natural habitats. One of the major causes of environmental degradation in India could be attributed to rapid growth of population, which is adversely affecting the natural resources and environment.Adverse effects on species diversity,Conversion of habitat to some other land use such as agriculture, urban development, forestry operation. In India, 70-80 per cent of fresh water marshes and lakes in Gangetic flood plains had been lost in last 50 years.Consequences of population growth are acidification,Ozone Depletion,Urbanization,Change due to disposal of waste material,Desertification, Water Supply,Food Security and nutrition.

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References

Nagdeve, A. D. Population Growth and Environmental Degradation in India.http://paa2007.princeton.edu/papers/7192
Coker, A. O. Environmental pollution: types, causes, impacts and management for the health and socio-economic well-being of Nigeria.http://tandice bsolutions.com/rokdownloads/ National Conference on the Environment.
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Anwar, F., Chaudhry, F.N., Nazeer, S., Zaman, N. and Azam, S. 2016. Causes of Ozone Layer Depletion and Its Effects on Human: Review. Atmospheric and Climate Sciences, 6, 129-134. http://dx.doi.org/10.4236/acs.2016.61011
Jagdish C. Katyal and Paul L.G. Vlek, 2000. Desertification – Concept, Causes and Amelioration, ZEF – Discussion Papers On Development Policy No. 33, Center for Development Research, Bonn, pp. 65.
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Suggesting Readings

Ehrlich, P. R., &Holdren, J. P. (1971).Impact of population growth.
Cropper, M., & Griffiths, C. (1994).The interaction of population growth and environmental quality.
The American Economic Review, 84(2), 250-254.
Pimentel, D., Huang, X., Cordova, A., & Pimentel, M. (1997).Impact of population growth on food supplies and environment. Population & Environment, 19(1), 9-14.
Hawley, A. H. (1982). Ecology.
Botkin, D. B., & Keller, E. A. (1998). Environmental science: earth as a living planet (No. Ed. 2).John Wiley & Sons Ltd.